Basic Electrical Things

[Jon Wehrenberg]

Joe,

Whether it is 12 V or 24 V doesn't it come from the house 12V batteries?

Usually the house 24V stuff is powered by 2 pair of 12V batteries wired on series.???

[Joe Cannarozzi]

Yeeeeeeeeeeeeeeeeeees

I have 8 12 volt batterys for the house.

2 sets of 4. 1 set are paralleled for the 12volt stuff.

And the other 4 are wired as you describe, parraleled and in series for the 24volt stuff.

I must be confusing the issue because you of all people should get it

[Joe Cannarozzi]

Right when you think you have things pretty cleaned up this happens.

My Bus 262.jpg

This is what I have exposed by pulling the 8 house batteries. More nastyness about the engine and starter and it looks like those last 4 batts for the bus that remain will be coming out too With all those batteries out I can get right at the powersteering pump plunger that is dripping. Powerwashing sanding and repainting are also in order. I wonder if Elgin has a part # for frame paint?

I've also decided to improve that battery tray for the house batterys by fabbing it just enough oversize to add additional inner trays that are the current dimension so that I can slide them out, top tray bottom tray.

My Bus 261.jpg

The hoses off the OTR A/C compressor go right through that tray, you have to take the tray apart or disconnect those hoses to get it out. The hoses go under the top tray but above the bottom batteries. Currently one has a protective cover and one does not.

I don't like that at all but I gotta deal with it. I don't think they enjoy battery crud. I'll cover them better to protect them as much as I can and then just keep things clean around them.

If anyone out there knows of a way that I could convienienty isolate the 8 house batteries from eachother when not in use I would be interested in knowing.

[Jon Wehrenberg]

I'm pulling this idea out of thin air Joe, but there are battery disconnects that attach to battery posts. I have seen the knife type and a type that has a wheel or knob that you turn. They are sold as a way to protect your car from theft or to turn off the battery for storage.

You would need one for each battery, but that might work.

What is missing in your pictures and I hope you have is a master battery switch and circuit breaker for each battery set located as close to the batteries as possible.

A weak link in circuit protection on all of our coaches is the cabling from the battery post to the circuit breaker or battery disconnect. That cable length needs to be as short as possible. I'll tell you why at Branson.

[JIM CHALOUPKA]

Joe, the marine industry has some nice battery disconnect switches available.

[JIM CHALOUPKA]

Joe, Don't be looking for OEM paint. Here find links to two superior products that are worthy of your time and effort.

http://www.rustbullet.com/IndTesting/Q-lab/Q-Lab.htm

http://www.por15.com/

Be sure to wear gloves as the paint will not come off your skin for weeks!!

[Joe Cannarozzi]

OK heres one for all you electrical wizards.
The two diagrams below are:

FIRST-the way prevost has the 4-12 volt batterys wired for 24 volt for the bus.

SECOND-the way the converter has the 4-12 volt batteries wired for 24 volt for the house.
My Bus 273.jpg
As you can see they aint the same, guess there is more than 1 way to achive 24 volt out of 4-12 volt batteries.

Another curious thing I've noticed. Our house voltage meters for 12volt and 24volt read 12.9 and 25.5 respectivly.

When I start the bus but before throwing the equalizer switch they go up to 13.1 and 26.9.

When the equalizer switch is turned on, with the bus running, they go up again to 13.6 and 27.1.

Why do they go up after the bus is started but before the equalizer is turned on?

[Jon Wehrenberg]

The batteries look the same. Two pair of series connected batteries in parallel.

I can only speculate on the voltages. When the engine is running but not the equalizer you are charging the batteries from the bus alternator, but when you turn the equalizer on the full alternator output is entering all batteries. I assume a 12V alternator?

[Joe Cannarozzi]

I'm pretty sure we have the gear driven oil cooled 450amp. 24volt monster.

Here is a pic of an old post showing it, before the leak was repaired.
My Bus 130.jpg

[Ray Davis]

The batteries look the same. Two pair of series connected batteries in parallel.

I think I'm disagreeing here. Definately both make 24 volts but in left hand side, we have 1+2 in parallel (12v), 3+4 in parallel (12v), and those two parallel circuits are in series to provide 24v

On the right hand side we have 1 and 2 in series (24v), 3 and 4 in series (24v), and the 2 24v combinations in parallel (still 24v)

So, in one case we have two pair of series connected bats in parallel (right side), and the other is two pair of parallel connected batteries in series.

Is one better than the other? Shoot, I don't have a clue. The left side for me was easier to decipher!

Ray